Polymer Materials; Structure and Properties:
Research Activities in Materials Science Laboratory
2018–2020: An Overview
Yutaka Tanaka: mail: tanaka(@)matse.u-fukui.ac.jp
Bachelor students. Five. M.C. students: Four.(2014)
[ Research Areas ]
(1) Rheology in Hydrocolloids.
It is well-known that many
polymers, synthetic and natural, form physical, thermoreversible aggregates in
dilute solutions, whereas, in moderately concentrated solutions, gels can be
formed. Various terms are
used in the literature for the development of a network structure; they are,
ageing, annealing, maturation, and so on, that is, network formation is clearly
time dependent. We always
elucidate the relationship between the mechanical properties and the network
formation in the hydrocolloid.
References.
(i) Dynamic mechanical properties of aqueous gellan solutions in the sol-gel transition region; K. Nakamura, Y. Tanaka, M. Sakurai, Carbohydrated Polym.; 30(2/3), 101-108(1996)
(ii)
Measurement of
stress and strain during tensile testing of gellan gum gels: effect of
deformation speed; M. Teratsubo, Y. Tanaka,
(iii) Effects of Deformation Rates on the Stress - Strain Curves and the Failure Properties in the Tensile Test of Gellan Gum Gels; Y. Tanaka, N. Mitamura, S. Saeki, Trans. Mat. Res. Soc. Jpn., 27[3], 581-584(2002)
(iv) Viscoelastic Properties for Sol-Gel Transition; Y. Tanaka, Rheology; InTech-open access publisher//www.intechweb.org, Chap.2., pp.29-58(2012)
(2) Gel Point Prediction .
Interpretation of the networkformation and gel points in the polycondensation system is carried out to account for unequal reactivity of the monomer and the ring structure in the network. An example of the polymerisation can be found for an epoxy – amine system based on the diglycidyl ether and the diamine, which is broadly used in the industry.
References.
(i) Measurements and Interpretation of Gel Points of an Epoxy-Amine System Accounting For Ring Formation; Y. Tanaka, Gel Sympo 2007 - Polymer Gels: Fundamentals and Functional Control, Abstracts, 67-68(2007)
(ii) Interpretation of Gel Points of an Epoxy-Amine System Including Ring Formation and Unequal Reactivity: Reaction Scheme and Gel-Point Prediction; Yutaka Tanaka, John L. Stanford, Robert Stepto, Macromolecules, 45, 7186-7196(2012)
(iii) Interpretation of Gel Points of an Epoxy-Amine System Including Ring Formation and Unequal Reactivity: Measurements of Gel points and Analyses on Ring Structures; Yutaka Tanaka, John L. Stanford, Robert Stepto, Macromolecules, 45, 7197-7205(2012)
(***) References can be downloaded (PDF file): http://matse.u-fukui.ac.jp/~bussei/res-activity/ResActivity.htm
(1) Glass transition and Plastic Processing.
Glasses are disordered materials that lack the periodical order of
crystals but behave mechanically like solids. The most common way of making a
glass is by cooling a viscous liquid fast enough to avoid crystallization. Although this route to the
vitreous state – supercooling – has been known for a long time, the molecular
processes by which liquids acquire amorphous rigidity upon cooling are not
fully understood. More
specifically, key problem is the relation between thermal history and the
structural relaxation. To
elucidate the structural relaxation problem leads to the fatigue prediction of
plastic.
References.
(i) Enthalpy Relaxation of Liquid Crystalline Polymer with Cyanobiphenyl Group in the Side Chain: Activation Energy Spectrum Analysis; Y. Tanaka, Polym. J., 39(10), 1030-1039(2007)
(ii) Enthalpy Relaxation of Liquid Crystalline Polymer with Cyanobiphenyl Group in the Side Chain: Analysis based on Configurational Entropy Model with the AG Expression; Y. Tanaka, Polym. J., 41(2), 1-7(2009)
(iii) Enthalpy Relaxation of Comb-like Polymer Analysed by Combining Activation Energy Spectrum and TNM models; Y. Tanaka and T. Yamamoto, J. Non-Crystal. Solids., 358, 1687-1698(2012)
(iv) Enthalpy Relaxation near the Glass Transition for Comb-like Polymer; Power Law Relaxation Revealed by DSC Experiment; Y. Tanaka, H. Asano, Y. Okuya / J. Non-Crystalline Solids, 363, 147-151.(2013)
(2) A Thin Film with a Potential of Controlling Light 
Transmittance .
A film sample is prepared from a comb-like polymer to investigate transparent/opaque change in response to thermal history. It has a potential application for a thin film to control the light transmittance.
References.
(i) Light Transmittance for Films of Liquid Crystalline Polymer having Cyanobiphenyl Group in the Side Chain; Y. Tanaka, Y. Yukimoto, Trans. Mat. Research Soc. Jap., 37[3] 495-498(2012)
BZ-Laboratory.